That only works when the size is around one MB. If size is 1200000 bytes i get "1.2MB".
But how to make it dynamic if let say file size is 46 byte.

UPDATE
Howto show a size of 46 Bytes like this 0.000046MB or show 500KB like this 0.5MB.
This has to be done on-the-fly. I want the user friendly output to always show X.XMB
regardless of how many Bytes.